Preparing color pages expressed in a Page Description Language (PDL) such as PostScript for printing is more time-consuming than for the equivalent black-and-white system. Some of the additional time spent is simply preparing more color planes. Additional operations to resolve interactions between color planes, such as overprinting and trapping, also add to the processing time. Prior to this invention, color printing systems simply took longer when processing monochrome pages. In some cases the user was required to manually disable additional operations when pages were known to be monochrome.
An automated method for deciding how to process a page optimally was needed.